The Westland District council says the area's water infrastructure is struggling to cope with increased tourist numbers over the summer months.
The Westland District Group manager of District Assets, David Inwood, said the water supply was reliant on the surrounding rivers and streams and was weather dependent.
Mr Inwood said residents will soon find that the water supply is under considerable strain, as was experienced last year, and water savings will be necessary.
The district's water infrastructure struggled to cope with increasing tourist numbers alongside typical water use, he said.
Mr Inwood said the council was in the process of applying for financial assistance from the Government's Tourism Infrastructure Fund to upgrade storage capacity and resilience, but this money can only be used for capital expenditure on structural components and won't solve the immediate problems.
The council is also applying to the fund for money to improve supplies for Haast, Franz Josef and Fox. He said in those communities water supply issues are already creating a potential risk to fire fighting.
Mr Inwood said when there are immediate issues alerts will be sent via text, Facebook and the council website.